Research On Electromagnetic Scattering Characteristics Of Clustered Dust Particles

Dust particles exist in every corner of our living environment and affect our lives all the time.The electromagnetic scattering problem of clustered dust particles has been a research topic of widespread concern in recent years.The electromagnetic scattering properties of electromagnetic waves in clustered dust particles is closely related to the space exploration,laser communication,electromagnetic wave transmission,and other fields.In this thesis,the electromagnetic scattering characteristics of clustered dust particles are studied,and the main work is as follows:1.Based on the Mie theory,the single scattering characteristics of cosmic dust particles under incidence of terahertz wave are studied in this thesis.We compare the similarities and differences of Mie scattering phase function and Double Henyey-Greenstein scattering phase function of cosmic dust particles under the incidence of Terahertz wave.We discuss the effects of incident wave frequency and particle size on the scattering directivity of dust particles.The numerical results show that,as the incident wave frequency and particle size increase,the electromagnetic scattering of dust particles is increasingly concentrated in forward scattering range with scattering angle of 0-0.5 radian.2.Based on the Generalized Multiparticle Mie-solution(GMM)and the Metropolis Monte Carlo method,the effects of incident wave frequency,particle density,and particle size on the multiple scattering properties of clustered dust particles are investigated in this thesis.First,we use Metropolis Monte Carlo method to simulate the distribution of clustered dust particles,and then utilize GMM to calculate its important electromagnetic parameters.The numerical results show that,as the incident wave frequency,the particle density,and particle size increase,the value of scattering function near the scattering angle of 0 degree increase.The total absorption cross section,scattering cross section,and extinction cross section increase with the increase of particle density and particle size.3.We study the multiple scattering characteristics of clustered dust particles under the fractal growth model of Diffusion-Limited Clustered Aggregation(DLCA),and investigate the influence of the number of aggregates on the multiple scattering characteristics of dust particles.First,the distribution of dust particles under the fractal growth model of DLCA is realized by simulation.Then,the electromagnetic scattering parameters of dust particles are computed by the GMM.The computed results show that,if the number of dust particles in per unit volume is constant,as the number of aggregates increase,the value of their scattering function near the scattering angle of 0 degrees decrease.As the number of aggregates increase,the total scattering cross section and total extinction cross section of dust particles decrease.